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IS 4894 FOR CENTRIFUGAL FAN PDF

Comments. IS Code. Recent; Popular; Featured. IS – – Pallets for materials. Buy BIS IS (R) SPECIFICATION FOR CENTRIFUGAL FANS from SAI Global. Standard Air. Centrifugal fans for use in mines and hazardous atmospheres may requirt: additional requirements to be met, not covered by this standard.

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The method of measurement of the speed of fan shall be such that the speed of the fan is not appreci- ably affected.

In case of doubt, the tests shall be carried out at all voltages. Never- theless, fans made to work in higher cooling air tem- peratures may be regarded as complying with this specification provided the temperature-rise values are reduced corresponding to the increase in cooling air temperature.

These insulat- ing materials are detailed in IS: However, it has not been found possible to specify these limits at present on account of: The amendments issued to the previous edition of the standard have also been incorporated in this revision. Proper types of bearings should be used to ensure a reasonable amount of silent operation. If the fan is specified for two or more distinct rated voltages with three or more supply terminals, the tests shall be carried out at the most unfavourable voltage.

As type test, this test should preferably be done immediately after the temperature-rise test. Full text of ” IS The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control which is devised and super- vised by BIS and operated by the producer.

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The other limbs of the manometer shall be opened to the ambient atmosphere and the manometer reading shall be taken as equal to the average static pressure in the airway.

This requirement is applicable for all positions in the normal use. For Reynolds numbers of and above, the coeffi- cient of discharge is 0″ and will cover the majority of fan tests.

Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. This value shall fall within the range of specified tolerances.

IS – – Centrifugal fans | QuestIn

The guards shall be securely attached and shall be adequately rigid to resist accidental contact with ls blades. The test voltage shall be applied as follows: Note — In this specification, si term ‘fan’ shall be used to mean centrifugal fan as supplied, without any addition to the inlet or outlet, except where such addition is specified. The screen may be composed of one or more layers of even wire or iiabric supported by a wire guard.

The criterion of noise level may, therefore, be subject to an agreement between the manufac- turer and the purchaser. In the case of a double insulated fan, both basically insulated parts and live parts shall not be accessible to the standard test finger. Note — Nevertheless, fans made for other freque- ncies shall be considered to comply with the specifica- tion provided they do so in all other relevant respects.

In the case of inductance type regulator, it is essential that no portion of the inductive winding should remain permanently short-circuited in any of the running positions. However, if regulators are required, this shall be a matter of agreement between the purchaser and the supplier.

This revision has been undertaken to take into account the experience gained since then and to align some of the safety requirements with the provisions of IS: The resistance measurement shall be made with a current of lOA with a dc voltage not exceeding 6V. The fixed losses and copper losses shall be calculated in accordance with the details given in IS: In the case of indirectly driven fans, the electric motor shall conform to the relevant Indian Standard, 1.

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The difference between the inlet volume flow at the intersection and the specified inlet volume flow that is, the duty point shall be recorded as the measure of departure of the fan from the specified perfor- mance. Such an addition shall then be regar- ded as a part of the fan. The absolute pressure of the ambient atmosphere is the barometric pressure.

The openings – shall be flush with the duct and free from burrs and countersinks. Such fans shall be specially marked. All metallic parts associated with it shall be protected from accidental contact. When the guards are in two pieces, positive locking arrangement to keep the two pieces together should be cenrifugal. The handle or knob shall be so designed that it does not become loose in use.

This test shall be carried out with the guard if any, in position.

IS 4894: Centrifugal fans

While taking the current and watt read- ings during these tests, however, the voltage shall be maintained at the test voltage. Part 1 Methods of testing performance’, issued by the British Stand- ards Institution. Intermediate values of d, may be obtained by linear interpolation. Capacitors shall comply with IS: